For five days, 16-year-old Luis Navarro Jr. slept next to his new Kawasaki dirt bike, which was parked between his bed and a shelf brimming with Spiderman figurines in the basement.

Navarro, who was studying to be a mechanic in vocational school, loved his shiny green-and-black motorcycle more than anything, family members say.

Police now believe the $3,000 motorcycle may be the reason a robber or robbers killed him when he was riding on a dirt trail in Tacony Creek Park in Feltonville shortly after 7 p.m. Saturday.

Police Sgt. Tim Cooney said yesterday that the boy was shot multiple times in the back. He had no criminal record. There are no suspects.

The homicide was one of several in another bloody weekend in Philadelphia. Five more homicides since the early hours of Saturday morning brought the city's soaring murder total to 242 this year. The latest was a woman found dead in Fairmount Park yesterday atop a pile of burned trash.

At Navarro's home in the 4600 block of Pennhurst Street, family members and friends gathered in the living room to grieve. No one remembered exactly why his mother, Caroline Navarro, gave him the motorcycle last week - it wasn't his birthday. When she learned the youngest of her three children had died violently, the 38-year-old woman became hysterical and had to be hospitalized in Albert Einstein's crisis center.

She may have been rewarding her son for good grades - family members said he got all A's and B's - or maybe it was just because he had wanted the motorcycle for so long and had stayed out of trouble.

His father, Luis Navarro Sr., 40, said the couple had given the teenager motor-scooters in the past so that he wouldn't be tempted to use drugs. Bicycles and motorcycles were his passion.

"He didn't do any drugs. He was never in the streets, selling drugs like many young people around here," said Navarro. "We always gave him everything he wanted so he wouldn't get in any trouble. But look what happened."

The man sat on a step, clinging to a white undershirt, a giant hankie of sorts that still couldn't contain his many tears. For a few minutes he struggled to find his voice.

"I would always tell him to be careful when he went to the trails, and if someone comes up to you, you don't stop. You keep going and get out of the woods," said Navarro, noting that the trails were only two or three blocks from home. He recalled that four years ago a man was shot and killed in the same park because a robber wanted the man's motor-scooter.

Navarro wonders whether his son loved his new motorcycle so much that he refused to surrender it to the robber. Or was he just trying to speed away and escape?

Navarro recalled how he had instructed his son to come home early because the family was going to his father's house in New Jersey. "We were waiting for him to come back," Navarro said.

While he was waiting, Navarro drove to a local store for a quick purchase and learned about the shooting in the woods.

"I went there and parked my car and ran through the woods calling Cito's name," he said, explaining that Cito was his son's nickname. "But the police didn't want me to go through the woods and see him there. They stopped me. I thought he was wounded, but then I heard one of the officers say they took him to the morgue."

Navarro said a crowd gathered and some people told him that several teens had run out of the woods when the shooting began. The four-wheel-drive vehicle of his son's companion was also stolen, he said.

Yesenia Navarro, 20, said her brother would have been a junior at Mastbaum Area Vocational Technical School in the fall. She said he played football on the school team in his freshman year and had worked at an auto-parts junkyard. "He was a nice person. He was really nice," she said, breaking down.

"He was one of my best friends. He was so nice he would fix bikes for people. He fixed a flat for my little sister," said Nashie Luna, 17, who lives nearby.

For interactive maps showing Philadelphia's 2007 shootings and homicides, visit http://go.philly.com/violenceEndText